Association between immune-related adverse events and survival in patients with renal cell carcinoma treated with nivolumab plus ipilimumab: immortal time bias-corrected analysis

Background Immune-related adverse events (irAEs) in patients treated with immune check inhibitors are associated with favourable response rate and survivals in multiple cancers, including renal cell carcinoma (RCC). The aim of this study was to investigate how irAEs were associated with improved survivals in advanced RCC patients treated with nivolumab plus ipilimumab. Materials and methods This retrospective study included patients who received nivolumab plus ipilimumab at six centres, institutions, or hospitals between September 2018 and February 2022. We assessed associations of the development and the number of irAEs with overall survival (OS) and progression-free survival (PFS). To eliminate immortal time bias, landmark analysis and a Cox model with time-dependent variables were used. Results This study included 129 patients with a median follow-up of 12.3 months. The 2-year OS and PFS rates were 55% and 42%, respectively. Ninety six patients experienced irAEs. The development of irAEs was positively associated with OS and PFS rates (hazard ratio [HR] 0.328, 95% confidence interval [CI] 0.165–0.648, p = 0.001; HR 0.334, 95% CI 0.151–0.737, p = 0.007). Patients who experienced multiple irAEs had longer OS (HR 0.507, 95% CI 0.235–1.097, p = 0.085 or HR 0.245, 95% CI 0.110–0.544, p < 0.001) and PFS (HR 0.572, 95% CI 0.316–1.036, p = 0.085 or HR 0.267, 95% CI 0.113–0.628, p = 0.002) compared with those who experienced single or zero irAE. Conclusions Developing irAEs, particularly multiple irAEs, is associated with favourable survivals in advanced RCC patients treated with nivolumab plus ipilimumab.